Answer:
A triangle is equilateral if all three angles are same. but here two angles are 64° but third angle is 52°. so, Yin is incorrect.
Step-by-step explanation:
x = 19,
Putting value of x to find m∠ABC and m∠ACB
m∠ABC = (4x – 12)°
m∠ABC = (4(19) – 12)°
m∠ABC = (76 – 12)°
m∠ABC = 64°
m∠ACB = (2(19) + 26)°
m∠ACB = (38 + 26)°
m∠ACB = 64°
now we know sum of angles of triangle is 180°. We can find the measure of third angle.
180 = 64+64 +x
x= 180 - 64 - 64
x = 52°
A triangle is equilateral if all three angles are same. but here two angles are 64° but third angle is 52°. so, Yin is incorrect.
B 1/2
Step-by-step explanation:
Answer:
The volume of the solid is 243
Step-by-step explanation:
From the information given:
BY applying sphere coordinates:
0 ≤ x² + y² + z² ≤ 81
0 ≤ ρ² ≤ 81
0 ≤ ρ ≤ 9
The intersection that takes place in the sphere and the cone is:



Thus; the region bounded is: 0 ≤ θ ≤ 2π
This implies that:

ρcosФ = ρsinФ
tanФ = 1
Ф = π/4
Similarly; in the X-Y plane;
z = 0
ρcosФ = 0
cosФ = 0
Ф = π/2
So here; 
Thus, volume: 

![V = \bigg [-cos \phi \bigg]^{\pi/2}_{\pi/4} \bigg [\theta \bigg]^{2 \pi}_{0} \bigg [\dfrac{\rho^3}{3} \bigg ]^{9}_{0}](https://tex.z-dn.net/?f=V%20%3D%20%5Cbigg%20%5B-cos%20%5Cphi%20%20%5Cbigg%5D%5E%7B%5Cpi%2F2%7D_%7B%5Cpi%2F4%7D%20%20%5Cbigg%20%5B%5Ctheta%20%20%5Cbigg%5D%5E%7B2%20%5Cpi%7D_%7B0%7D%20%5Cbigg%20%5B%5Cdfrac%7B%5Crho%5E3%7D%7B3%7D%20%20%5Cbigg%20%5D%5E%7B9%7D_%7B0%7D)
![V = [ -0+ \dfrac{1}{\sqrt{2}}][2 \pi -0] [\dfrac{9^3}{3}- 0 ]](https://tex.z-dn.net/?f=V%20%3D%20%5B%20-0%2B%20%5Cdfrac%7B1%7D%7B%5Csqrt%7B2%7D%7D%5D%5B2%20%5Cpi%20-0%5D%20%5B%5Cdfrac%7B9%5E3%7D%7B3%7D-%200%20%5D)
V = 243
The best sampling strategy would be a stratified sample.
<h3>How are samples classified?</h3>
Samples may be classified as:
- Convenient: Drawn from a conveniently available pool.
- Random: All the options into a hat and drawn some of them.
- Systematic: Every kth element is taken.
- Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.
- Stratified: Also divides the population into groups. Then, a equal proportion of each group is surveyed.
For this problem, the 4 different brands of the recorders must be considered, hence the buyers should be divided into groups, and a proportion of each group should be sampled, hence a stratified sample should be used.
More can be learned about sampling at brainly.com/question/25122507
#SPJ1